Polymetric notation

Polymetric notation is supported explicitly or by manually modifying the visible time signature symbol and/or scaling note durations.

Different time signatures with equal-length measures

Set a common time signature for each staff, and set the timeSignatureFraction to the desired fraction. Then use the \scaleDurations function to scale the durations of the notes in each staff to the common time signature.

In the following example, music with the time signatures of 3/4, 9/8 and 10/8 are used in parallel. In the second staff, shown durations are multiplied by 2/3 (because 2/3 * 9/8 = 3/4) and in the third staff, the shown durations are multiplied by 3/5 (because 3/5 * 10/8 = 3/4). It may be necessary to insert beams manually, as the duration scaling will affect the auto-beaming rules.

\relative <<
  \new Staff {
    \time 3/4
    c'4 c c |
    c4 c c |
  }
  \new Staff {
    \time 3/4
    \set Staff.timeSignatureFraction = 9/8
    \scaleDurations 2/3 {
      \repeat unfold 3 { c8[ c c] }
      \repeat unfold 3 { c4 c8 }
    }
  }
  \new Staff {
    \time 3/4
    \set Staff.timeSignatureFraction = 10/8
    \scaleDurations 3/5 {
      \repeat unfold 2 { c8[ c c] }
      \repeat unfold 2 { c8[ c] } |
      c4. c \tuplet 3/2 { c8[ c c] } c4
    }
  }
>>

Different time signatures with unequal-length measures

Each staff can be given its own independent time signature as soon as \enablePolymeter is placed in the \layout block.

\layout {
  \enablePolymeter
}

% Now each staff has its own time signature.

\relative <<
  \new Staff {
    \time 3/4
    c'4 c c |
    c4 c c |
  }
  \new Staff {
    \time 2/4
    c4 c |
    c4 c |
    c4 c |
  }
  \new Staff {
    \time 3/8
    c4. |
    c8 c c |
    c4. |
    c8 c c |
  }
>>

To have just one polymetric score, include \enablePolymeter in a \layout block inside the \score block.

\score {
  <<
    \new Staff { c''1 1 }
    \new Staff { c'2 d' g'2~ 2 }
  >>
}

\score {
  \layout {
    \enablePolymeter
  }
  <<
    \new Staff { \time 4/4 c''1 1 }
    \new Staff { \time 2/4 c'2 d' g'2~ 2 }
  >>
}

When using polymeter, all staves should include a \time command if their meter is not the default 4/4. This is true even for special staves without actual staff lines, such as Dynamics contexts, since the placement of certain spanners like hairpins is synchronized with bar lines.

In order to use this feature with MIDI output, also include \enablePolymeter in a \midi block.

\layout {
  \enablePolymeter
}

\midi {
  \enablePolymeter
}

Compound time signatures

These are created using the \compoundMeter function. The syntax for this is:

\compoundMeter #'(list of lists)

The simplest construction is a single list, where the last number indicates the bottom number of the time signature and those that come before it, the top numbers.

\relative {
  \compoundMeter #'((2 2 2 8))
  \repeat unfold 6 c'8 \repeat unfold 12 c16
}

More complex meters can be constructed using additional lists. Also, automatic beaming settings will be adjusted depending on the values.

\relative {
  \compoundMeter #'((1 4) (3 8))
  \repeat unfold 5 c'8 \repeat unfold 10 c16
}

\relative {
  \compoundMeter #'((1 2 3 8) (3 4))
  \repeat unfold 12 c'8
}

See also

Music Glossary: polymetric, polymetric time signature, meter.

Notation Reference: Automatic beams, Manual beams, Time signature, Scaling durations.

Snippets: Rhythms.

Internals Reference: TimeSignature, Timing_translator, Staff.

Known issues and warnings

Although notes that occur at the same moment in each of the different staves will be placed at the same horizontal location, bar lines (in each staff) may cause inconsistent spacing within each of the different time signatures.